The calculated distance (air line) between Al Ḩudaydah and Zabīd is approximately 48 miles respectively 77 kilometers.
By car or train, the actual journey to Zabīd is certainly longer, as only the direct route (as the crow flies) between Al Ḩudaydah and Zabīd has been calculated here.
Air line (approximately)
77 kilometers
42 nautical miles